I've noticed my C100mk2 wants to pull towards blue/magenta. Here's a white balance test that seems to confirm it. White balance settings in the bottom right, then the correction applied by Resolve in the bottom left (using the white balance picker on the top right square, *correction bypassed in the images*). Image linked to below.

AWB is very blue, with a magenta tint.

Applying the same temperature in custom WB gets closer and, weirdly, is more accurate along green/magenta (AWB should get this closer).

The daylight preset (5500K) is much more accurate.

Finally, a grey card reading gets closest, just a touch too warm/green. When I tried this test for the first time, the grey card reading was almost perfect, perhaps because I filled more of the frame with the grey card.

You are aware that you can program in RGB offsets easily in your picture profiles, right? While it make take some experimentation, the C100 and C100 MKII can be color matched and I agree with your assessment, the C100 MKI veers much more toward red with a yellow bias to skin tones while the C100 MKII is decidedly cooler and more magenta skin tones. Just shoot some chip charts, tweak and customize your picture profiles and you should be able to arrive at colors that suit your preference.